Ultrasonic Testing in lieu of Radiographic Testing...Ultrasonic Testing in lieu of Radiographic...
Transcript of Ultrasonic Testing in lieu of Radiographic Testing...Ultrasonic Testing in lieu of Radiographic...
Ultrasonic Testing in lieu of Radiographic TestingMartin van den Heuvel MISI-Consultancy
KINT Symposium October 2019
Agenda
Ultrasonic Testing in lieu of Radiographic Testing: ‘UT ilo RT’
▪ NIL Thin Plate
▪ Innovation in NDT
The case for change
▪ Why use UT ilo RT
▪ Suitable UT Techniques
Business Cases
▪ Project
▪ Maintenance
Way forward
▪ Collaboration
UT in lieu of RT: historic information
NIL Thin Plate project 1992
Objectives
▪ To assess the reliability of mechanized ultrasonic inspection. in comparison with the 'standard' non-destructive inspection techniques (i.e. standard radiography and manual UT) for detection of defects in welds in steel plate in the wall thickness range 6-15 mm.
▪ To contribute to the development of suitable acceptance/rejectance criteria and, if necessary, initiate their implementation criteria in national and international regulations on non-destructive testing
Conclusion
▪ The detection reliability of mechanized ultrasonic testing techniques is at least as good as but usually better than that of conventional non-destructive testing techniques such as manual ultrasonic testing and standard radiography.
Improvements since 1992
▪ Mechanized (PA)UT is standardized and thus reliable Automated UT (AUT) and semi-automated UT with encoded scan enables permanent record keeping of UT inspection data
▪ Data storage is now common practice
Innovation in NDT (These Wassink 2012)
Key points
▪ It takes a long time to develop and implement changes in NDT applications
▪ Collaboration of all parties is key, the Cyclic Innovation Model is a way to shorten the time
▪ Entrepreneurs are needed to make it a success
Why use RT in lieu of UT
RT in lieu of UT?
Historic performance, we have done it so many years with good outcomes
▪ Large capacity of experienced inspectors
▪ Common practice, less preparation needed, flexible in application
▪ Cheaper teams and equipment compared to UT
▪ Less limitations on geometry/size versus UT
New developments in (digital) radiography
▪ Fast films
▪ Lower radiation exposure and shorter distances
▪ Digital imaging and filing
Field weld inspection
▪ Plot clearance is required → delay for construction
▪ Long backlog of inspection work and feedback to welders
▪ No opportunity for welders to improve on weld quality!
▪ RT quality issues when gamma radiation is used, (3mm double wall, 160 KeV X-ray. Ir 480 KeV, Se 200 KeV)
Shop weld inspection
RT is either done:
▪ In the night → backlog + delay construction
▪ In a bunker → logistics
RT inspection is slow
RT uses radiation:
major HSSE risk→ plot clearance /
bunker
RT is not sensitive to
planar defects
Why use UT in lieu of RT
Production Schedule
▪ No plot clearance required, welding can continue
▪ Fast inspection (20-40 welds per shift) → no backlog
HSSE risks
▪ No radiation risks
Quality
▪ No backlog: direct feedback to welders
▪ Improved quality: finds critical planar defects
Mechanised and Encoded UT solves these issues:
RT: no direct feedback
UT: direct feedback, dropping rejection due weld
quality
Time
Rej
ecti
on
rate
Suitable UT technologies
TOFD
(PA)UT
Time Of Flight Diffraction (TOFD)
Advantages
• High POD and low False call rate
• High Accuracy of Flaw Location and Flaw Sizing
• All inspection Results/Data is Digitized and Stored and can be Recalled and Processed for In-Service Inspection
• Most efficient for inspection of thick-walled vessels where X & Gamma ray would have difficulties
Limitations
• Difficult for thin welds <9mm thickness.
• Sizing of shallow crack close to the inspection surface is less accurate → use surface methods
• Need access to both side of the weld.
• Difficult/impossible for coarse grain materials
Mechanised PAUT
Advantages
• Array transducer enables beam steering and focusing.
• Beam steering enables inspection from one probe location rather than raster scan
• Beam focusing enables increased sensitivity for small defects
• More user friendly and versatile signal display(C scan, B scan, A scan, Sector scan) for defect location, characterization, and sizing.
• All inspection Results/Data can be digitized and stored so that the permanent record can be kept.
Limitations
• Equipment pricing is relatively higher
• Need more extensive operator training
• Difficult for coarse grained materials
Examples in this conference
Day 1
▪ Doosan Babcock: Applications with qualifications conform ENIQ criteria
▪ TUV Rheinland Sonovation: project on thin walled stainless steel, significant savings
Day 2
▪ Gasunie: how UT ilo RT was implemented and is now common practice
▪ Olympus: This walled heat exchanger tubes
▪ Many technical presentations with background information to help understand the technological opportunities and restrictions
▪ Several companies will present their strategic approach
Application case Prelude
Outcomes UT in lieu of RT:
• 100.000 inspected piping field welds on Prelude, of which:
• 50% was 100% inspection scope
• 50% was 10% inspection scope
UT in lieu of RT was applied for:
• 2000 carbon steel welds
• 60 stainless steel welds
Only 2% of total scope !
• GAP between opportunity <-> realization
UT ilo RT for Piping
The business case for projects
• Significant reduction of QA/QC time
• Direct feedback to the welder
• Cost savings
• Direct cost per weld
• Logistics for piping
• 24 hrs/day available for welding and NDT
• If UT inspection is considered in the design stage the outcomealso enhances capability for in service inspection.
• Improves life cycle safety and cost of inspection. Eg root corrosion of welds
Application case Steam Boiler repair
Situation
• Overhaul of internals in steam boiler, Low alloy steel, 1”-2”diameter and 3.4mm –11mm wall thickness, thousands welds in scope
• RT scope on critical path, enormous impact on schedule
• PAUT knowledge available
• Regulator agreed with deviation from code which required RT inspection →qualification needed
• Time required before overhaul starts
Impact
• 1 (of 5) month construction time reduction
• Significant cost saving, Lower HSSE risk
• Qualification can be replicated and re-used
Implementation
• Increase the knowledge of QA/QC staff of end users
• Explain business cases, simple showcases, gain (€) support for qualifications
• Development of standards with acceptance criteria
• Collaboration between end users and technology suppliers
Thank you for your attention
Martin van den HeuvelPrincipal Asset Management Consultant
MISI: Maintenance and Inspection Strategic ImprovementZuiderstraat 179444 PJ GrollooTel. +31 6 14288215www.MISI-Consultancy.nl